137a8b710f
The simplifier was performing an optimization to replace bitselect with vselect if the all bytes of the condition mask could be shown to be all ones or all zeros. This optimization only ever made any difference in codegen on the x64 target. Therefore, move this optimization to the x64 back-end and perform it in ISLE instead. Resulting codegen should be unchanged, with slightly improved compile time. This also eliminates a few endian-dependent bitcast operations.
This crate contains the core Cranelift code generator. It translates code from an intermediate representation into executable machine code.